Package org.eclipse.persistence.jpa.jpql.parser

Class RangeVariableDeclaration

  • All Implemented Interfaces:
    Expression
    public final class RangeVariableDeclaration
extends AbstractExpression
    Range variable declarations allow the developer to designate a "root" for objects which may not be reachable by navigation. In order to select values by comparing more than one instance of an entity abstract schema type, more than one identification variable ranging over the abstract schema type is needed in the FROM clause.

    JPA:

    BNF: range_variable_declaration ::= abstract_schema_name [AS] identification_variable

    EclipseLink 2.4:

    BNF: range_variable_declaration ::= { root_object } [AS] identification_variable
    BNF: root_object ::= abstract_schema_name | (subquery)
    Since:
    2.3
    Version:
    2.5
    Author:
    Pascal Filion

    • Constructor Detail

      • RangeVariableDeclaration

        public RangeVariableDeclaration​(AbstractExpression parent)
        Creates a new RangeVariableDeclaration.
        Parameters:
        parent - The parent of this expression

      • RangeVariableDeclaration

        public RangeVariableDeclaration​(String entityName,
                                String variableName)
        Creates a new RangeVariableDeclaration, which is used as a virtual declaration.
        Parameters:
        entityName - The name of the entity to be accessible with the given variable name
        variableName - The identification variable used to navigate to the entity

    • Method Detail

      • getActualAsIdentifier

        public String getActualAsIdentifier()
        Returns the actual AS found in the string representation of the JPQL query, which has the actual case that was used.
        Returns:
        The AS identifier that was actually parsed, or an empty string if it was not parsed

      • getIdentificationVariable

        public Expression getIdentificationVariable()
        Returns the Expression that represents the identification variable.
        Returns:
        The expression that was parsed representing the identification variable

      • getRootObject

        public Expression getRootObject()
        Returns the Expression that represents the "root" object.
        Returns:
        The expression that was parsed representing the "root" object

      • hasAs

        public boolean hasAs()
        Determines whether the identifier AS was parsed.
        Returns:
        true if the identifier AS was parsed; false otherwise

      • hasIdentificationVariable

        public boolean hasIdentificationVariable()
        Determines whether the identification variable was parsed.
        Returns:
        true if the identification variable was parsed; false otherwise

      • hasRootObject

        public boolean hasRootObject()
        Determines whether the "root" object was parsed.
        Returns:
        true if the "root" object was parsed; false otherwise

      • hasSpaceAfterAs

        public boolean hasSpaceAfterAs()
        Determines whether a whitespace was parsed after AS.
        Returns:
        true if there was a whitespace after AS; false otherwise

      • hasSpaceAfterRootObject

        public boolean hasSpaceAfterRootObject()
        Determines whether a whitespace was parsed after the "root" object.
        Returns:
        true if there was a whitespace after "root" object; false otherwise

      • hasVirtualIdentificationVariable

        public boolean hasVirtualIdentificationVariable()
        Determines whether this identification variable is virtual, meaning it's not part of the query but is required for proper navigability.
        Returns:
        true if this identification variable was virtually created to fully qualify path expression; false if it was parsed

      • setVirtualIdentificationVariable

        public void setVirtualIdentificationVariable​(String variableName)
        Sets a virtual identification variable because the "root" object was parsed without one. This is valid in an UPDATE and DELETE queries. Example:

        UPDATE DateTime SET date = CURRENT_DATE

        is equivalent to

        UPDATE DateTime d SET d.date = CURRENT_DATE

        Parameters:
        variableName - A virtual identification variable that will identify the "root" object

      • setVirtualIdentificationVariable

        public void setVirtualIdentificationVariable​(String variableName,
                                             String path)
        Sets a virtual identification variable to qualify the "root" object. The "root" object is a derived path that does not start with an identification variable. Example:

        UPDATE Employee SET firstName = 'MODIFIED' WHERE (SELECT COUNT(m) FROM managedEmployees m) > 0

        'managedEmployees' is a derived path and will become qualified with the given virtual identification variable.

        Parameters:
        variableName - The identification variable that was generated to qualify the "root" object
        path - The path that was parsed as a "root" object